Axially arranged rotary threshing or separating systems have long been in use in agricultural combines for threshing crops to separate grain from crop residue, also referred to as material other than grain (MOG). Such axially arranged systems typically include at least one cylindrical rotor rotated within a cage or concave, with the rotor and surrounding concave being oriented so as to extend forwardly to rearwardly within the combine.
During operation of the combine, crop material is fed or directed into a circumferential passage between the rotor and the concave and is carried rearwardly along a generally helical path through such passage by rotation of the rotor as grain is threshed from the crop material. The flow of crop residue remaining between the rotor and concave after threshing is typically discharged or expelled at a rear or downstream end of the rotor. After discharge from the threshing system, the crop residue is typically directed into a crop residue distribution system located below and rearwardly of the rear end of the rotor. The crop residue distribution system typically includes a rotary beater or chopper or other apparatus that conveys or chops the residue into smaller pieces and propels the crop residue rearwardly towards an area within the rear end of the combine, hereinafter referred to as a distribution chamber. The crop residue provided within the distribution chamber may either be discharged onto a field as a windrow or directed into a spreader mounted on or at the rear end of the combine that is operable for spreading the residue over a swath of the field.
Combines are typically configured to harvest crops with vastly different material properties, which can make it difficult to control the spread distribution and/or spread width of the crop residue discharged from the combine's spreader. For example, light weight crops, such as wheat, create a low density residue which is much more difficult to spread over a large distance than heavier crops, such as corn, that create a relatively dense residue. To accommodate such different material properties, many conventional spreaders include motors configured to rotate the spreader's discs at variable speeds. These motors are typically required to be capable of rotating the spreader discs at a relatively high speed to discharge low density residues widely while also being capable of rotating the spreader discs at a relatively low speed to prevent high density residues from being discharged too widely. As such, the variable-speed motors utilized in such conventional spreaders can be relatively expensive. Moreover, to prevent crop residue from being discharged too widely, the speed settings for the spreader disks must be carefully tailored to match the material properties of the particular crop being harvested, which is often a difficult and time consuming task.
Accordingly, a system and method that is capable of controlling the spread distribution and/or spread width of crop residue without requiring the rotational speed of the spreader discs to be adjusted would be welcomed in the technology.